external/ibm-public/postfix/dist/html/regexp_table.5.html

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   7 REGEXP_TABLE(5)                                                REGEXP_TABLE(5)
   8
   9 <b>NAME</b>
  10        regexp_table - format of Postfix regular expression tables
  11
  12 <b>SYNOPSIS</b>
  13        <b>postmap -q "</b><i>string</i><b>" <a href="regexp_table.5.html">regexp</a>:/etc/postfix/</b><i>filename</i>
  14
  15        <b>postmap -q - <a href="regexp_table.5.html">regexp</a>:/etc/postfix/</b><i>filename</i> &lt;<i>inputfile</i>
  16
  17 <b>DESCRIPTION</b>
  18        The Postfix mail system uses optional tables  for  address
  19        rewriting,  mail  routing, or access control. These tables
  20        are usually in <b>dbm</b> or <b>db</b> format.
  21
  22        Alternatively, lookup tables can  be  specified  in  POSIX
  23        regular  expression form. In this case, each input is com-
  24        pared against a list of patterns. When a match  is  found,
  25        the  corresponding  result  is  returned and the search is
  26        terminated.
  27
  28        To find out what types of lookup tables your Postfix  sys-
  29        tem supports use the "<b>postconf -m</b>" command.
  30
  31        To  test  lookup  tables,  use the "<b>postmap -q</b>" command as
  32        described in the SYNOPSIS above.
  33
  34 <b>COMPATIBILITY</b>
  35        With Postfix version 2.2 and earlier specify "<b>postmap -fq</b>"
  36        to  query  a  table that contains case sensitive patterns.
  37        Patterns are case insensitive by default.
  38
  39 <b>TABLE FORMAT</b>
  40        The general form of a Postfix regular expression table is:
  41
  42        <b>/</b><i>pattern</i><b>/</b><i>flags result</i>
  43               When <i>pattern</i> matches the input string, use the cor-
  44               responding <i>result</i> value.
  45
  46        <b>!/</b><i>pattern</i><b>/</b><i>flags result</i>
  47               When <i>pattern</i> does <b>not</b> match the input  string,  use
  48               the corresponding <i>result</i> value.
  49
  50        <b>if /</b><i>pattern</i><b>/</b><i>flags</i>
  51
  52        <b>endif</b>  Match the input string against the patterns between
  53               <b>if</b> and <b>endif</b>, if and only if that same input string
  54               also matches <i>pattern</i>. The <b>if</b>..<b>endif</b> can nest.
  55
  56               Note:  do not prepend whitespace to patterns inside
  57               <b>if</b>..<b>endif</b>.
  58
  59               This feature is available in Postfix 2.1 and later.
  60
  61        <b>if !/</b><i>pattern</i><b>/</b><i>flags</i>
  62
  63        <b>endif</b>  Match the input string against the patterns between
  64               <b>if</b> and <b>endif</b>, if and only if that same input string
  65               does <b>not</b> match <i>pattern</i>. The <b>if</b>..<b>endif</b> can nest.
  66
  67               Note:  do not prepend whitespace to patterns inside
  68               <b>if</b>..<b>endif</b>.
  69
  70               This feature is available in Postfix 2.1 and later.
  71
  72        blank lines and comments
  73               Empty  lines and whitespace-only lines are ignored,
  74               as are lines whose first  non-whitespace  character
  75               is a `#'.
  76
  77        multi-line text
  78               A  logical  line starts with non-whitespace text. A
  79               line that starts with whitespace continues a  logi-
  80               cal line.
  81
  82        Each  pattern  is a POSIX regular expression enclosed by a
  83        pair of delimiters. The regular expression syntax is docu-
  84        mented  in  <b>re_format</b>(7)  with  4.4BSD,  in  <b>regex</b>(5) with
  85        Solaris, and in <b>regex</b>(7) with Linux. Other systems may use
  86        other document names.
  87
  88        The  expression  delimiter  can  be  any character, except
  89        whitespace or characters that have special meaning (tradi-
  90        tionally  the  forward slash is used). The regular expres-
  91        sion can contain whitespace.
  92
  93        By default, matching is case-insensitive, and newlines are
  94        not  treated  as  special characters. The behavior is con-
  95        trolled by flags, which are toggled by  appending  one  or
  96        more of the following characters after the pattern:
  97
  98        <b>i</b> (default: on)
  99               Toggles  the  case  sensitivity  flag.  By default,
 100               matching is case insensitive.
 101
 102        <b>m</b> (default: off)
 103               Toggle the multi-line mode flag. When this flag  is
 104               on,  the  <b>^</b>  and <b>$</b> metacharacters match immediately
 105               after and immediately before a  newline  character,
 106               respectively,  in addition to matching at the start
 107               and end of the input string.
 108
 109        <b>x</b> (default: on)
 110               Toggles the extended  expression  syntax  flag.  By
 111               default,  support for extended expression syntax is
 112               enabled.
 113
 114 <b>TABLE SEARCH ORDER</b>
 115        Patterns are applied in the order as specified in the  ta-
 116        ble,  until  a  pattern  is  found  that matches the input
 117        string.
 118
 119        Each pattern  is  applied  to  the  entire  input  string.
 120        Depending  on  the  application,  that string is an entire
 121        client hostname, an entire client IP address, or an entire
 122        mail  address.   Thus,  no parent domain or parent network
 123        search is done, and <i>user@domain</i>  mail  addresses  are  not
 124        broken  up  into  their <i>user</i> and <i>domain</i> constituent parts,
 125        nor is <i>user+foo</i> broken up into <i>user</i> and <i>foo</i>.
 126
 127 <b>TEXT SUBSTITUTION</b>
 128        Substitution of substrings  from  the  matched  expression
 129        into  the  result  string  is possible using $1, $2, etc.;
 130        specify $$ to produce a $ character as output.  The macros
 131        in  the  result  string  may need to be written as ${n} or
 132        $(n) if they aren't followed by whitespace.
 133
 134        Note: since negated patterns (those preceded by <b>!</b>)  return
 135        a result when the expression does not match, substitutions
 136        are not available for negated patterns.
 137
 138 <b>EXAMPLE SMTPD ACCESS MAP</b>
 139        # Disallow sender-specified routing. This is a must if you relay mail
 140        # for other domains.
 141        /[%!@].*[%!@]/       550 Sender-specified routing rejected
 142
 143        # Postmaster is OK, that way they can talk to us about how to fix
 144        # their problem.
 145        /^postmaster@/       OK
 146
 147        # Protect your outgoing majordomo exploders
 148        if !/^owner-/
 149        /^(.*)-outgoing@(.*)$/   550 Use ${1}@${2} instead
 150        endif
 151
 152 <b>EXAMPLE HEADER FILTER MAP</b>
 153        # These were once common in junk mail.
 154        /^Subject: make money fast/     REJECT
 155        /^To: friend@public\.com/       REJECT
 156
 157 <b>EXAMPLE BODY FILTER MAP</b>
 158        # First skip over base 64 encoded text to save CPU cycles.
 159        ~^[[:alnum:]+/]{60,}$~          OK
 160
 161        # Put your own body patterns here.
 162
 163 <b>SEE ALSO</b>
 164        <a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager
 165        <a href="pcre_table.5.html">pcre_table(5)</a>, format of PCRE tables
 166        <a href="cidr_table.5.html">cidr_table(5)</a>, format of CIDR tables
 167
 168 <b>README FILES</b>
 169        <a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
 170
 171 <b>AUTHOR(S)</b>
 172        The regexp table lookup code was originally written by:
 173        LaMont Jones
 174        lamont@hp.com
 175
 176        That code was based on the PCRE dictionary contributed by:
 177        Andrew McNamara
 178        andrewm@connect.com.au
 179        connect.com.au Pty. Ltd.
 180        Level 3, 213 Miller St
 181        North Sydney, NSW, Australia
 182
 183        Adopted and adapted by:
 184        Wietse Venema
 185        IBM T.J. Watson Research
 186        P.O. Box 704
 187        Yorktown Heights, NY 10598, USA
 188
 189                                                                REGEXP_TABLE(5)
 190 </pre> </body> </html>